Electrode Plate, Secondary Battery Including Same, and Method for Manufacturing Secondary Battery

The present application claims priority to and the benefit of Korean Patent Application No. 10-2024-0073337, filed on Jun. 4, 2024, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated by reference herein.

Aspects of embodiments of the present disclosure relate to an electrode plate, a secondary battery including the electrode plate, and a method for manufacturing the secondary battery.

Unlike primary batteries that are not designed to be (re) charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable, small electronic devices, such as smart phones, feature phones, notebook computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and for storing power (e.g., home and/or utility scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case accommodating the same, and electrode terminals connected to the electrode assembly.

To connect each of the electrode terminals to the electrode assembly (e.g., a jelly roll), a metal tab including nickel or aluminum is welded to an uncoated section of an electrode plate where an active material is not applied. However, cracks may occur in the electrode plate due to accumulated stress in the electrode plate.

The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute related (or prior) art.

In a structure of an electrode assembly of a secondary battery, at parts where thickness differences may occur—such as a Ni/AI tab attachment part, a protective tape attachment part, and cutting portions of the electrode plate and a mixture section thereof—accumulated stress due to an expansion and contraction of the electrode plate that may be caused by the insertion and extraction of lithium (Li) ions during charging and discharging may occur. The accumulated stress may eventually cause cracks in the electrode plate.

For example, protective tapes, such as PE, PP, or PVC, or lamination tapes, being made of a similar material to that of the separator, may fuse with the separator due to a pressure generated during the expansion of the electrode assembly. The fusion may lead to a high friction resistance, thereby hindering the natural sliding of a positive electrode plate and a negative electrode plate, which have different expansion and contraction rates from each other. Consequently, the stress at the stepped parts (e.g., the parts where thickness differences may occur) may increase. As a result, the electrode assembly may deform, causing short circuits, which in turn, may degrade the safety and reliability of the secondary battery.

Embodiments of the present disclosure may be directed to an electrode plate, a secondary battery including the electrode plate, and a method for manufacturing the secondary battery.

However, the technical problem to be solved by the present disclosure is not limited to the above problem, and other problems not mentioned herein, and aspects and features of the present disclosure that would address such problems, will be clearly understood by those skilled in the art from the description of the present disclosure below.

According to one or more embodiments of the present disclosure, an electrode plate includes: a mixture section where an active material is on a substrate; an uncoated section where the active material is not on the substrate; a tab coupled to the uncoated section; and a resin layer on the mixture section.

In an embodiment, the resin layer may include a fluororesin layer or a silicone resin layer.

In an embodiment, the resin layer may include the fluororesin layer, and a coefficient of friction of the fluororesin layer may be 0.1 or less.

In an embodiment, the fluororesin layer may include polytetrafluoroethylene (PTFE).

In an embodiment, the electrode plate may further include a protective tape covering the tab and the uncoated section, and the resin layer may be located on the protective tape.

In an embodiment, the protective tape may include a first edge portion defined by a step difference between the tab and the uncoated section, and the resin layer may be located on the first edge portion.

In an embodiment, the protective tape may include a second edge portion defined by a step difference between the mixture section and the uncoated section, and the resin layer may be located on the second edge portion.

In an embodiment, the protective tape may include a third edge portion defined by a step difference between the mixture section and the protective tape, and the resin layer may be located on the third edge portion.

In an embodiment, the resin layer may be located on an end edge portion of the electrode plate.

In an embodiment, the resin layer may be located on an active material edge portion defined by a step difference between the mixture section and the uncoated section.

According to one or more embodiments of the present disclosure, a secondary battery includes: an electrode assembly including a separator wound with electrode plates of different polarities from each other; a can accommodating the electrode assembly; and a cap assembly coupled to the can, and connected to the electrode assembly. Each of the electrode plates includes: a mixture section where an active material is on opposite surfaces of a substrate; an uncoated section where the active material is not on the substrate; a tab coupled to the uncoated section; and a resin layer on the mixture section.

In an embodiment, the resin layer may include a fluororesin layer or a silicone resin layer with a coefficient of friction of 0.1 or less.

In an embodiment, the secondary battery may further include a protective tape covering the tab and the uncoated section, and the resin layer may be located on the protective tape.

In an embodiment, the resin layer may be located on an end edge portion of each of the electrode plates.

In an embodiment, the resin layer may be located on an active material edge portion defined by a step difference between the mixture section and the uncoated section.

In an embodiment, the resin layer may be located at a winding core or an outer periphery of the electrode assembly.

According to one or more embodiments of the present disclosure, a method for manufacturing a secondary battery, includes: unwinding a first substrate; coating a first active material on the first substrate; coating a resin on the first substrate coated with the first active material to produce a first electrode plate; and winding the first electrode plate together with a second electrode plate and a separator.

In an embodiment, the coating of the resin may include a spray coating.

In an embodiment, the coating of the resin may include a wet coating using a coating solution.

In an embodiment, the method may further include a drying process after the first electrode plate is produced.

According to some embodiments of the present disclosure, the resin layer may be formed on the protective tape of the electrode plate. Therefore, it may be possible to prevent or substantially prevent a stress that may be caused due to an increased friction caused by a fusion of the separator at stepped portions during the contraction and expansion of the electrode plate in the charging and discharging cycles of the secondary battery.

According to some embodiments of the present disclosure, a cracking of the electrode plate may be prevented or reduced, thereby improving the safety and reliability of the secondary battery.

According to some embodiments of the present disclosure, the resin layer may include (e.g., may be made of) a low-friction polytetrafluoroethylene (PTFE) or silicone material. Therefore, it may be possible to reduce the friction resistance between the electrode plate, the separator, and the protective tape attachment area, thereby inducing a natural slipping due to the expansion and contraction of the electrode plate.

According to some embodiments of the present disclosure, it may be possible to reduce a cracking of the electrode plate by distributing the stress concentration in the stepped portions.

However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by a person skilled in the art from the detailed description, described below 262624/412299

Hereinafter, embodiments of the present disclosure will be described, in detail, with reference to the accompanying drawings. The terms or words used in the present specification and claims are not to be limitedly interpreted as general or dictionary meanings and should be interpreted as meanings and concepts that are consistent with the technical idea of the present disclosure on the basis of the principle that an inventor can be his/her own lexicographer to appropriately define concepts of terms to describe his/her invention in the best way.

The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure and do not represent all of the technical spirit, aspects, and features of the present disclosure. Accordingly, it should be understood that there may be various equivalents and modifications that can replace or modify the embodiments described herein at the time of filing this application.

It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected, or coupled to the other element or layer or one or more intervening elements or layers may also be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being “coupled” or “connected” to a second element, the first element may be directly coupled or connected to the second element or the first element may be indirectly coupled or connected to the second element via one or more intervening elements.

In the figures, dimensions of the various elements, layers, etc. may be exaggerated for clarity of illustration. The same reference numerals designate the same elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Further, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions, such as “at least one of” and “any one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. When phrases such as “at least one of A, B and C, “at least one of A, B or C,” “at least one selected from a group of A, B and C,” or “at least one selected from among A, B and C” are used to designate a list of elements A, B and C, the phrase may refer to any and all suitable combinations or a subset of A, B and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Also, any numerical range disclosed and/or recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein. All such ranges are intended to be inherently described in this specification such that amending to expressly recite any such subranges would comply with the requirements of 35 U.S.C. § 112(a) and 35 U.S.C. § 132(a).

References to two compared elements, features, etc. as being “the same” may mean that they are “substantially the same”. Thus, the phrase “substantially the same” may include a case having a deviation that is considered low in the art, for example, a deviation of 5% or less. In addition, when a certain parameter is referred to as being uniform in a given region, it may mean that it is uniform in terms of an average.

Throughout the specification, unless otherwise stated, each element may be singular or plural.

Arranging an arbitrary element “above (or below)” or “on (under)” another element may mean that the arbitrary element may be disposed in contact with the upper (or lower) surface of the element, and another element may also be interposed between the element and the arbitrary element disposed on (or under) the element.

In addition, it will be understood that when a component is referred to as being “linked,” “coupled,” or “connected” to another component, the elements may be directly “coupled,” “linked” or “connected” to each other, or another component may be “interposed” between the components”.

Throughout the specification, when “A and/or B” is stated, it means A, B or A and B, unless otherwise stated. That is, “and/or” includes any or all combinations of a plurality of items enumerated. When “C to D” is stated, it means C or more and D or less, unless otherwise specified.

The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the scope of the present disclosure.

Embodiments of the present disclosure are applicable to both winding-type and stacked-type batteries. Embodiments related to electrodes are applicable to electrodes included in winding-type batteries or stacked-type batteries.

In the present disclosure, the sizes and relative dimensions of layers and regions shown inmay be exaggerated for clarity of explanation. That is, the sizes shown inare for the sake of convenience of understanding and are not intended to limit the scope of the present disclosure. Furthermore, throughout the specification, like reference numerals will be given to like parts.